Spatial navigation involves multiple cognitive processes including multisensory integration, visuospatial coding, memory, and decision-making. These functions are mediated by the interplay of cerebral structures that can be broadly separated into a posterior network (subserving visual and spatial processing) and an anterior network (dedicated to memory and navigation planning). Within these networks, areas such as the hippocampus (HC) are known to be affected by aging and to be associated with cognitive decline and navigation impairments. However, age-related changes in brain connectivity within the spatial navigation network remain to be investigated. For this purpose, we performed a neuroimaging study combining functional and structural connectivity analyses between cerebral regions involved in spatial navigation. Nineteen young (μ = 27 years, σ = 4.3; 10 F) and 22 older (μ = 73 years, σ = 4.1; 10 F) participants were examined in this study. Our analyses focused on the parahippocampal place area (PPA), the retrosplenial cortex (RSC), the occipital place area (OPA), and the projections into the visual cortex of central and peripheral visual fields, delineated from independent functional localizers. In addition, we segmented the HC and the medial prefrontal cortex (mPFC) from anatomical images. Our results show an age-related decrease in functional connectivity between low-visual areas and the HC, associated with an increase in functional connectivity between OPA and PPA in older participants compared to young subjects. Concerning the structural connectivity, we found age-related differences in white matter integrity within the navigation brain network, with the exception of the OPA. The OPA is known to be involved in egocentric navigation, as opposed to allocentric strategies which are more related to the hippocampal region. The increase in functional connectivity between the OPA and PPA may thus reflect a compensatory mechanism for the age-related alterations around the HC, favoring the use of the preserved structural network mediating egocentric navigation. Overall, these findings on age-related differences of functional and structural connectivity may help to elucidate the cerebral bases of spatial navigation deficits in healthy and pathological aging.

中文翻译：

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空间导航脑网络中功能和结构连接的年龄相关差异。

空间导航涉及多个认知过程，包括多感官整合，视觉空间编码，记忆和决策。这些功能由大脑结构的相互作用介导，大脑结构可以广泛地分为后路网络（用于视觉和空间处理）和前路网络（用于记忆和导航计划）。在这些网络中，已知诸如海马（HC）的区域会受到衰老的影响，并与认知能力下降和导航障碍相关。但是，与年龄相关的空间导航网络中的大脑连接性变化仍有待研究。为此，我们进行了神经影像学研究，将参与空间导航的大脑区域之间的功能和结构连接性分析相结合。19岁（μ= 27岁，σ= 4.3；在这项研究中检查了10 F）和22岁（μ= 73岁，σ= 4.1； 10 F）的参与者。我们的分析集中在海马旁位置区域（PPA），脾后皮质（RSC），枕骨位置区域（OPA）以及从独立功能定位器划定的中央和周边视野的皮层投影。此外，我们从解剖学图像中分割了HC和内侧前额叶皮层（mPFC）。我们的结果显示，与低年龄段的参与者相比，低视力区域与HC之间的年龄相关的功能连通性下降，与OPA和PPA之间的功能连通性增加相关。关于结构连通性，我们发现导航大脑网络中白质完整性的年龄相关差异，但OPA除外。已知OPA参与以自我为中心的导航，这与与海马区域更相关的同素中心策略相反。因此，OPA和PPA之间功能连接的增加可能反映了HC周围与年龄相关的变化的补偿机制，有利于使用保留的结构网络来协调以自我为中心的导航。总体而言，这些关于年龄相关的功能和结构连接差异的发现可能有助于阐明健康和病理性衰老中空间导航缺陷的大脑基础。因此，OPA和PPA之间功能连接的增加可能反映了HC周围与年龄相关的变化的补偿机制，有利于使用保留的结构网络来协调以自我为中心的导航。总体而言，这些与年龄相关的功能和结构连接性差异的发现可能有助于阐明健康和病理性衰老中空间导航缺陷的大脑基础。因此，OPA和PPA之间功能连接的增加可能反映了HC周围与年龄相关的变化的补偿机制，有利于使用保留的结构网络来协调以自我为中心的导航。总体而言，这些与年龄相关的功能和结构连接性差异的发现可能有助于阐明健康和病理性衰老中空间导航缺陷的大脑基础。